Insulator.



FRED M. LOCKE, OF VICTOR, NEW YORK.

Patented May 8, 191 '7 INSULATOR.

1,225,141 Specification of Letters Patent. 1 mi Drawing.

To all whom it may concern:

Be it known that I, FRED M. Looks, a citizen of the United States, andresident of Victor, in the county of Ontario, in the State of New York,have invented new and useful Improvements in Insulators, of which thefollowing is a full, clear, and exact description.

This invention relates to certain improvements in insulators and refersmore particularly to a composition electric insulation as a new articleof manufacture and is closely related to my copending application,Serial No. 845,371 filed June 16, 1914, and reference is hereby made tomy cop application, Serial No. 482,382, filed March 9, 1909 formanufacture of high potential porcelain and glass insulators whichapplication has matured into Letters Patent No. 1,120,951, 1,127,042 and1,156,163, and reference is further made to my Letters Patent No.1,091,678, dated March 31, 1914: and No. 1,091,679, dated March 31,1914, respectively.

The primary object of the invention is to produce a composition materialsusceptible of varioususes, but particularly for insulators for highpotential electric conductors which is unaffected by temperature andclimatic changes, and to increase for insulating purposes its inductivecapacity, dielectric strength and resistance to puncture ordisintegration by electric current and reduce its coeflicient ofexpansion: I Glass of nearly all kinds has a large co efiicient ofexpansion and cracks easily from sudden changes in temperature,rendering it unsuitable under many and various conditions for insulatingpurposes. Pure silica, however, has a very small coeflicient ofexpansion and can stand all temperature changes from red heat to verycold without cracking.

A further object, therefore, of this invention is to produce a glass orporcelain of high silica content to prevent cracking from sudden changesof temperature.

In glasses containing 70 or 75% of silica, it requires very high heatand long firing to fuse and it is hard to form them into shape anddiflicult to eliminate bubbles, owing to the viscosity of the mass. Ihave discovered that by the use of a body of the halogen group or of ahalogen compound, I can flux silica very easily and shape 11; whilesoft, owing to the affinity ofthe elements of ending Application filedSeptember 4, 1914. Serial No. 860,160.

the halogen group, with particular reference to fluorin, or halogencompounds for silica and aluminum. Under fusion, I am enabled to formthese materials into a homogeneous body at a low heat. For example: In abatch mixture of the following weights, 80%silica; 17% cryolite; 3%boric acid, I find that after fusion the mass contains from analysis 90%of silica. Referring to this particular example, cryolite comprises morethan 50% of fiuorin and in this instance, fluorin, or as otherwisedetermined some other halogen element, seems to have disappeared fromthe'mass when the latter becomes cool, leaving a high content of silica,and in this example, a small amount of aluminum and sodium and theincorporated boron.

That this is the true explanation, and that the halogen body largelydisappears by volatilization is clearly shown by the very.

small percentage of such body in the composition mass, and the furtherfact that under fusion the silica and halogen compound quickly andeasily come to a fluid state, but that long continued fire will bringthe fluid back to a thick rubbery state that is much harder to mold andform than at the earlier stages of the firing. This change from fluidstate to a thick rubbery state is accounted for by the volatilizationofthe halogen element.

Glass of low expansion coeificient is nearly all very low in alkalis andinvariably glass of high expansion coefficient embodies largepercentages of alkalis. I have-found that by the use of cryolite I canreadil fuse a mix comprising seventy per cent. 0%) or more of silica andproduce a glass which is low in alkali and has a very smallexpansibility,say not to exceed .0000050. I account for this bythe factthat fluorin, which constitutes more than fifty per cent. (50%.) ofcryolite, has a cat afiinity for silica and during, or afitier, fluxingthe fiuorin is vaporized leaving substantially the sodium oxid andalumina, which are the other constituents of cryolite. For example, Ihave found that by using say five parts of cryolite I can flux a greateramount of silica or alumina than if I used five parts of ordinary flux,such as sodium carbonate, and the resulting glass made with will be muchlower in alkali and of erably lower expansion coefficient.

considcryolite contains the glass of high silica content and very lowcoeflicient of expansion,' -say not greater than .0000050, due. to'therelatively small amount of alkali used, by fusing silica material, boronmaterial, and cryolite,

I may use in combination with silica any of the following elements:fluorin, chlorin,

;eliicient of expansion and at the same time a very good insulator,superior as regards specific inductive capacity and dielectric strengthto either glass or porcelain.

To the composition above despribed, I add boron or boron in some of itscompound forms, ranging in amount from 1% to 60%.

in accordance with the specific inductive ca pacity, etc., required, tofurther increase in combination with the other elements the specificinductive capacity and dielectric strength and to decrease thecoefiicient of expansion. In tests Which I have made relative to theincorporation of boron in insulator bodies, I find that with a 10 inchdisk insulator formed of a composition including boron,- it required110,000 volts to are around, while with a 10% inch disk of the bestporcelain it requires only 90,000 volts, and with a glass disk of thesame size only 80,000 volts.

These last advantages result froma combination of the fact that underfusion boron forms no compound with hydrogen with the further fact thatwhen the electric current is applied to the insulator, it affects theatmosphere or atmosphere surrounding the insulator and separates it intoions. Now boron or compounds of boron have the property of preventingionization of the atmosphere, thereby proportionately increasing theamount of voltage the insulator will stand. And preferably to theelements above set forth either in elemental or compound forms, I add asmall percentage of soda or potash to increase the ease and rapidity ofthe fusing operation.

In my copending application, Serial No. 845,371, I have claimed a glassor an insulator formed by fusing silicic material, beron material andhalogen material to afOI'IIl a homogeneous body. This application broadclaims to the product together with specific claims for cryolite as thehalogen-carrying element of the com-- bination.

For the purpose of forming an insulator having a high content of silicacombined with aluminum, I may fuse feldspar, or any other aluminumsilicate, with fiuorin material, or some other of the halogen elementsor compounds; .or, I may fuse silica or a compound of silica withcryolite, or with a halogen element'or compound, incombination withaluminum, and I desire to claim herein broadly the fusion of silica andaluminum, either in elementary form or any compound forms, with an-element of the halogen group or ahalogen compound, and allpreferably incombination with boron or boron in some of its compound forms, such asborax or boracicacid, and for the purpose of this application and theclaims hereto appended a compound of any of the elements herein claimedis deemed the full equivalent of the element as claimed, and may be usedin substitution therefor without departing from the spirit of theinvention as herein described and claimed.

What I claim is:

1. An insulator of high silica content formed by fusing silicic materialwith cryolite and boron material to form a homogeneous body and moldingthe mass to desired form.

2. An insulator of high silica content formed by fusing silicic materialwith cryolitej andboron material to form a homogeneous body.

3. A vitreous body formed by fusing silicic material with'cryolite andboron material to form a homogeneous body.

4. The method of forming a homogeneous body of high silica contentconsisting in fusing silicic material, cryolite and boron material toform a homogeneous body.

5. An insulator for high voltage current formed by fusing silicicmaterial, boron maaercial and cryohte to form a homogeneous 6. A glasscomprising seventy or more per cent. of silica, boric oxid alumina, anda small amount of alkali, and having a coefficient. of expansion of lessthan .0000050.

7. An insulator for line conductors comprising silica, boron materialand cryolite fused together in a homogeneous body.

8. A glass formed by fusing a large percentage of silicic material, withboron material and cryolite to form a homogeneous body.

9. A glass comprising seventy or more per cent. of silica, alumina,boron oixid and a small amount of an alkali and having a coeflicient ofexpansion not greater than .0000050.

10. A glass of high silica content formed byfusing boron material,silicic material, alumina material, halogen material and a small amountof an alkali to form a homogeneous body.

11. A heat resisting glass of low co-eficient of expansion comprisingboron oxid,

alumina, a small amount of an alkali and a relatively large amount of*silica and having a coefficient of expansion not greater than .0000050.

12. A heat-resisting glass of low coeficient of expansion comprisingboron oxid, alumina, sodium oxid, a relatively large percentage ofsilica and a small percentage of potassium oxid and having a coeiiicientof expansion not greater than .0000050.

13. A vitreous body of 10W coeflicient of expansion formed by fusingsilicic material With cryolite, boron material, and an alkali to form ahomogeneous body.

14. A vitreous body of 'loW coefficient of expansion formed by fusingsilicic material with cryolite, boron material and potassium material toform a homogeneous body.

15. An insulator for line conductors formed by fusing silidic materialwith cryolite, boron material, and an alkali to form a homogeneous body.

16 "An insulator for line conductors to form a homogeneous body.

17. A glass of low expansion coeficient formed by fusing silicicmaterial, boron.

material, cryolite and an alkali, and. showing from analysis silica,boric oxid, alumina and an alkali. r x

18. A glass formed by fusing silicic material, boron material, cryoliteand an alkali, and showing from analysis silica, boric oxid, alumina andan alkali, and having an expansion coeificient not greater than,0;000050.

' In Witness whereof I have hereunto set my hand this 29thjday of August1914:. y FRED M. LOCKE,

' Witnesses:

'W. A. HIGINBo'rHAM, E. C. Bmsron,

